Furuno FS-1570, Service Manual

Page: 157 / 322

5.6 W/R board (05P0734)
5-40
Fig.5.6.2 Input vs. output on W/R Board
PLL circuit
The PLL circuit consisting of DDS and PLL, operates with the reference signal of 18
MHz from REF OSC board.
The PLL oscillates at the frequency range from 56.0615 to 81.955 MHz, using four
oscillation coils, T501 to T504. The oscillation frequency depends on the frequency
setting. BAND H/L signal selects the VCO circuit for the lower or higher frequency
range in each band.
Table 5.6.1 PLL oscillation frequencies
BAND Setting frequency (MHz) Oscillation frequency (MHz)
1-L 1.6065 to 2.99999 56.06150 to 57.45499
1-H 3.0 to 5.99999 57.45500 to 60.45499
2-L 6.0 to 9.49999 60.45500 to 63.95499
2-H 9.5 to 13.49999 63.95500 to 67.95499
3-L 13.5 to 17.49999 67.95500 to 71.95499
3-H 17.5 to 21.49999 71.95500 to 75.95499
4-L 21.5 to 25.49999 75.95500 to 79.95499
4-H 25.5 to 27.50000 79.95500 to 81.95500